The term advertise is a verb that means to announce publicly or give the public notice of something.
In marketing, it specifically refers to the public promotion of a product, service or event. Of course, the main reason behind advertising is not just to provide information to the public, though that is the means, but to influence the public to buy a company’s goods or services.
The usual advertising channels include TV broadcasts (both infomercials and covert or placement ads), radio, newspapers, magazines, industry journals, billboards (including mobile billboards), the internet (from search engine ads to online games and social media ads), and the point of purchase.
Point of purchase advertisements are those located in the place where people buy or avail of the product itself, like in supermarkets, where you will hear jingles and see flyers and posters, to get people to pay more attention to their product instead of their competitors.
Another effective form of advertising are celebrity endorsements. Advertisers pay celebrities to endorse their products if they determine that a particular celebrity has a big enough following, and that the fan base is representative of the company’s target market. The only problem is that such endorsements can backfire if the celebrity falls out of grace, in which case the companies usually pull out ads showing the celebrity.